This disclosure relates generally to a synchronous machine, and more specifically to a control system for synchronizing current supply with rotor position.
Synchronous machines are known. Synchronous machines include a stationary portion and a rotating portion, where the rotating portion and the stationary portion each have at least one winding.
One application of synchronous machines is a starter/generator arrangement for gas turbine engines. Synchronous starter/generators are configured to function as a motor to first start a gas turbine engine. Once the engine is running, the synchronous starter/generator can be shifted to operate the machine as a generator.
An example of a synchronous machine includes a direct current (DC) synchronous machine. When operating as a generator, the DC synchronous machine is configured to supply direct current to one or more loads such as avionics equipment or motor driven loads on an aircraft. When operating as a motor, the DC synchronous machine is coupled to a DC power source in order to supply motive power to a device with moving parts, such as the starter function, or a pump or compressor.
The DC synchronous machine includes an AC field winding on the rotating portion and a DC armature winding on the stationary portion. Current supplied to the AC field winding generates a magnetic field between the rotating portion and the stationary portion, causing direct current to be generated at the DC armature winding. Commutation of the AC field winding in DC synchronous machines typically requires one or more position sensors, such as resolver or Hall Effect devices, in order to synchronize a frequency of current supply with angular rotation of the rotor. There are complexities associated with integrating position sensors into electrical system.